This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
Robert, I have IM4.0.4 installed, and just ran convert with -negate -monochrome and produced a dithered image with the white background...so at one time it worked. You have a typo in -monochrome below which I assume is not your problem. Have you tried the Imagemagick mail list? You can also save yourself the step of converting a gempak gif to a white background if you use the gpcolor program to define the background as white beforehand, eg: % gpcolor COLORS = 101=white DEVICE = gf GEMPAK-GPCOLOR>r Creating process: gf for queue 4851 Parameters requested: COLORS,DEVICE. GEMPAK-GPCOLOR>e Now, when you run a gempak program, the background color (which is #101) will be white. Steve Chiswell Unidata User SUpport On Fri, 25 Jun 1999, Robert Mullenax wrote: > I had been using ImageMagick ver 3 on our Solaris Intel > machine to convert GEMPAK/McIDAS images with black backgrounds > to white backgrounds using the negate feature, or monochrome > to make it B&W. However, I obtained the latest relaese of ImageMagick > (ver 4.27) for our Sparc and it will not perform > the conversion properly, -negate -mnochrome produces a > completely black image on a GEMPAK(GARP) image with a > black background. Doing the same on our Intel machine > and IM 3.0 produces the desired B&W image. I also > tried IM 4.27 on another Solaris Intel machine with > the same results. > > Are there any other image viewer/converters out there > that can also be run from the command line for > use in scripts? I will also look for an older version > of ImageMagick. > > Thanks > Robert Mullenax >